This invention relates to generating multimedia documents using a computer system.
The computer system illustrated in FIG. 1--which includes mouse 15, keyboard 16, CPU 17 and CRT 18--represents a hardware setup for running software that allows a user to view and/or create multimedia documents. A multimedia document may include several different types of media arranged in a background setting to create an informative or aesthetically pleasing presentation. The media types may include text, images, movies, music or other sounds, animations, 3D virtual worlds, links to other objects, applets (self-contained executable programs written in Java--an interpreted computer language, or in the Java scripting language, JavaScript) and plug-ins (extension mechanisms for handling non-standard data types). One class of multimedia document is the hypertext-markup language (HTML) page (equivalently, a "web page"). HTML is a language used to create visually structured documents that can be viewed with a "browser"--an application for viewing and interacting with multimedia documents. A typical application for an HTML page is to publish it to a unique URL (uniform resource locator) address on the World Wide Web. This allows others--namely, either the general public or a limited group of people within an enterprise--to access the HTML page via the Internet.
FIG. 2A shows an example of a Silicon Graphics HTML page residing at the URL address
http://www.sgi.com/ss.home.page.html
The web page in FIG. 2A is viewed through an HTML browser (Netscape Navigator) which displays the web page in a window 20 and the corresponding URL address of the web page in address line 22. The user can specify the particular web page to be viewed by entering its URL address in the address line 22. Most web pages include links to other web pages or other resources (image files, movie files, sound files, etc.) on the internet. Each link points to a URL address associated with a document specified by the developer of the web page at the time of the page's creation. A user can access information pointed to by a link by clicking on it with a mouse cursor. In response, the browser automatically jumps to the corresponding URL address and displays the web page or otherwise accesses the resource at the specified URL. For example, when the user clicks on the link 24 in FIG. 2A labeled "company info & jobs," the browser jumps to the corresponding URL address and displays the web page listing corporate information in FIG. 2B.
Authoring web pages can be a challenging endeavor often requiring the HTML author to have extensive training and experience in the HTML programming language, which is somewhat arcane, as illustrated in FIG. 3 by the partial HTML source listing for the web page of FIG. 2A. To make web page authoring somewhat easier, visual HTML programming tools have been developed that do not require an author to understand the complexities of HTML. These tools simplify the process of developing web pages by enabling an author to generate multimedia documents through graphical user interface (GUI) abstractions and standard point-and-click cursor techniques.
FIG. 4A shows one such visual HTML page layout tool, the editor component of Netscape Navigator, providing a GUI window 40 having several different text and image manipulation tools 41 that may be used by an author along with conventional point-and-click mouse techniques to generate an HTML page in editing region 42. An author can generate a new HTML page from scratch, or edit an existing HTML page, by entering text 43 via the keyboard, importing pre-defined images 44 using various tools provided by the editor, specifying links 45 to other URL addresses, and using interactive cursor manipulation techniques to arrange and format the components in the desired fashion. Using the visual information provided by the author, the editor tool automatically generates an HTML source listing, shown in FIG. 4B, which describes the multimedia document shown in FIG. 4A.
Even with such visual HTML page layout tools, creating multimedia documents of any complexity can be a painstaking process, especially when a document contains several different media types in various formats, each requiring a different editing environment for its creation and modification. A sophisticated HTML page might contain objects of many different media types including text, images, movies, 3D virtual worlds and sounds. Each of these media types can be represented in any of several different formats--for example, images can be in any of the RGB, PNG, TIFF, GIF or JPEG formats among others, sounds can be in any of the WAV, MIDI or AU formats among others, and movies can be in MPEG-1, MPEG-2, AVI or MOV formats among others. To generate and subsequently modify the objects making up a web page, the author typically must invoke several editing programs, usually a different editor for each media type and potentially a different editor for different formats within the same media type.
Adding further to a web page author's burden is the fact that most commercially available HTML browsers support only a subset of the vast universe of formats available for the different types of media. Some HTML browsers only will have native support for JPEG and GIF formatted images, and, by means of readily available plug-ins, can be enhanced to support MPEG-1 format for movies, WAV format for sounds and VRML (virtual reality modeling language) format for 3D worlds. Consequently, an author may encounter an additional task whenever a web page component is created or edited-namely, converting objects from their native formats into standard formats understandable to a browser (i.e. "web-publishable" formats).